For the first question, the property of gas that allows them to be stored in a bottle of air freshener is that gases are compressible. They follow the volume where they are stored.
For the second question, at the molecular level the molecules of the ice cream gains more kinetic energy as it is melting turning it into a liquid where the molecules now are loosely packed and collisions of each molecule decreases. This process is called melting.
The third question defines a gas where the molecules are far from each other and are at constant random motion. Also, from the kinetic molecular theory there is no forces of attraction between the molecules for a gas.
